Highly functional hydrophilic polyisocyanates and their preparation

Abstract

The invention relates to hydrophilized polyisocyanates (P) obtainable from the reaction (U) of a component A), wherein the polyisocyanate is modified with allophane and optionally isocyanurate groups, having a proportion of allophane groups ≥ 50 mol%, preferably ≥ 50 mol% to ≤ 99 mol%, preferably ≥ 60 mol% to ≤ 98 mol%, particularly preferably ≥ 70 mol% to ≤ 98 mol%, in each case based on the total amount of allophane and isocyanurate groups in the modified polyisocyanate and determined by NMR spectroscopic analysis, and which is obtainable from the reaction (U') of components A1) a mixture of A11) at least one monomeric triol and A12) at least one monomeric diol, with A2) at least one monomeric diisocyanate, which is aliphatically and / or cycloaliphatically bonded has isocyanate groups, with a hydrophilizing agent B),wherein at least one non-ionically hydrophilizing compound has at least one isocyanate-reactive group. The invention also relates to the use of the hydrophilized polyisocyanates according to the invention in or as coating materials, sealants or adhesives.

Description

[0001] The invention relates to hydrophilized polyisocyanates (P) obtainable from the reaction (U) of a component A), wherein the polyisocyanate is modified with allophanate and optionally isocyanurate groups, having a proportion of allophanate groups ≥ 50 mol%, preferably ≥ 50 mol% to ≤ 99 mol%, preferably ≥ 60 mol% to ≤ 98 mol%, particularly preferably ≥ 70 mol% to ≤ 98 mol%, in each case based on the total amount of allophanate and isocyanurate groups in the modified polyisocyanate and determined by NMR spectroscopic analysis, and which is obtainable from the reaction (U`) of components A1) a mixture of A1 1) at least one monomeric triol and A1 2) at least one monomeric diol, with A2) at least one monomeric diisocyanate, which is aliphatic and / or cycloaliphatic, has bound isocyanate groups, with a hydrophilizing agent B),wherein at least one non-ionically hydrophilizing compound has at least one isocyanate-reactive group. The invention also relates to the use of the hydrophilized polyisocyanates according to the invention for the production of coatings, sealants or adhesives.

[0002] Monomeric diisocyanates are practically never used as crosslinking agents in polyurethane systems due to their volatility and toxicological properties. Higher molecular weight derivatives, modified with, for example, uretdione, isocyanurate, iminooxadiazine, urethane, or allophanate groups, are generally used. An overview of these polyisocyanates and their preparation methods is given, for example, in Laas et al., J. Prakt. Chem. 336, 1994, 185-200.

[0003] Due to the ecological and economic requirements for modern coating systems, which aim to use as little or no organic solvent as possible for viscosity adjustment, there is a desire to use already low-viscosity coating raw materials. Polyisocyanates with an allophanate structure, as described, among other places, in EP-A 0 682 012, have long been known for this purpose.

[0004] In industrial processes, these are produced by reacting a mono- or polyhydric alcohol with large quantities of excess aliphatic and / or cycloaliphatic diisocyanate (see GB-A 994 890, EP-A 0 000 194 or EP-A 0 712 840). Subsequently, unreacted diisocyanate is removed by vacuum distillation.

[0005] Allophane-based polyisocyanates can also be used to provide highly functional crosslinkers. Such systems often achieve particularly high resistance to chemicals or mechanical stresses. WO 2019 / 062383 A1 and EP 4 303 246 A1 describe allophane-modified polyisocyanates based on TMP. These are highly functional but also exhibit high viscosity. The former leads to end products with high hardness and high chemical resistance. However, the high viscosity makes handling the polyisocyanates difficult. Hydrophilized polyisocyanates are not described in either document.

[0006] One way to reduce or avoid the use of solvents is to use water-based polyisocyanates. These can be obtained by incorporating hydrophilic groups, as described, for example, in EP0206059A2. Here, isocyanurate-containing systems are modified with monofunctional polyethylene oxide polyethers and thus made hydrophilic.

[0007] Attempts have also been made to further enhance the functionality of such systems through allophantization in order to improve properties such as chemical resistance or scratch resistance (EP0959087A1, WO2001 / 40347). Such systems exhibit increased functionality and therefore increased resistance. However, this effect cannot be increased indefinitely because the underlying isocyanurate is polymerized via the allophantization reaction, thus continuously increasing its viscosity.

[0008] The object of the present invention was therefore to provide water-dispersible, highly functional, yet low-viscosity allophane-modified polyisocyanates that lead to end products, such as coatings, with high hardness and high chemical resistance.

[0009] This problem was solved by the subject matter of claim 1.

[0010] The present invention relates to hydrophilized polyisocyanates (P) obtainable from the reaction (U) A) a polyisocyanate modified with allophane and optionally isocyanurate groups, which has a proportion of allophane groups ≥ 50 mol%, preferably ≥ 50 mol% to ≤ 99 mol%, preferably ≥ 60 mol% to ≤ 98 mol%, particularly preferably ≥ 70 mol% to ≤ 98 mol%, in each case based on the total amount of allophane and isocyanurate groups in the modified polyisocyanate and determined by NMR spectroscopic analysis, and which is obtainable from the reaction (U`) A1) of a mixture of A1 1) at least one monomeric triol and A1 2) at least one monomeric diol, with A2) at least one monomeric diisocyanate having aliphatic and / or cycloaliphatic isocyanate groups, with B) at least one non-ionic hydrophilizing compound having at least one isocyanate-reactive group, optionally in the presence of C) at least one,the reaction of the isocyanate groups of component A) with the isocyanate-reactive groups of component B) accelerating catalyst and / or D) at least one auxiliary or additive. Mixture A1):

[0011] Monomeric triols, preferably with up to 15 carbon atoms, are used as component A1 1). Examples include: glycerol, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, 1,2,6-hexanetriol, 1,2,4- and 1,3,5-trihydroxycyclohexane, and 1,3,5-tris(2-hydroxyethyl)isocyanurate. 1,1,1-Trimethylolpropane is preferably used as component A1 1).

[0012] Monomeric diols, preferably with up to 15 carbon atoms, are used as component A1 2). Examples include: ester alcohols, such as glycerol monoacetate and glycerol monobutyrate; the isomeric butanediols, in particular 1,3-butanediol and 1,4-butanediol; the isomeric pentanediols, hexanediols, heptanediols and octanediols; 1,10-decanediol; 1,2- and 1,4-cyclohexanediol; 1,4-cyclohexanedimethanol; 4,4'-(1-methylethylidene)-biscyclohexanol; and bis-(2-hydroxyethyl)hydroquinone. Preferably, 1,3-butanediol and / or 1,4-butanediol are used as component A1 2).

[0013] In a preferred embodiment, the weight ratio of A1 1 ) to A1 2 ) is from 1 : 10 to 10 : 1, preferably from 1 : 5 to 5 : 1, particularly preferably from 1 : 2 to 2 : 1.

[0014] It is also possible to use other mono- and / or polyols with a functionality ≥ 4 A1') in the reaction (U`) in addition to the mixture A1), wherein their total proportion is a maximum of 20 wt.% (≥ 0 to ≤ 20 wt.%), preferably a maximum of 10 wt.% (≥ 0 to ≤ 10 wt.%), in each case based on the weight of the mixture A1).

[0015] Examples of such mono- and polyols with a functionality ≥ 4 (A1') include mono- or polyhydric alcohols with up to 15 carbon atoms, preferably 2 to 6 carbon atoms, such as methanol, ethanol, n-propanol, isopropanol, n-butanol, n-hexanol, 2-ethyl-1-hexanol; ether alcohols, such as 1-methoxy-2-propanol, 3-ethyl-3-hydroxymethyloxetane, tetrahydrofurfuryl alcohol; ester alcohols, such as ethylene glycol monoacetate, propylene glycol monolaurate, glycerin diacetate or 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate; unsaturated alcohols such as allyl alcohol, 1,1-dimethylallyl alcohol or oleic alcohol; araliphatic alcohols such as benzyl alcohol; tetrahydrofurfuryl alcohol; 2,2-Bis(hydroxymethyl)-1,3-propanediol, sorbitol, mannitol.

[0016] Mixtures of the above-mentioned alcohols A1') can also be used. Diisocyanate A2):

[0017] In this context, the term "aliphatic" is defined as non-aromatic hydrocarbon groups that are saturated or unsaturated.

[0018] In the present context, the term "alicyclic" or "cycloaliphatic" is defined as possibly substituted, carbocyclic or heterocyclic compounds or units that are not aromatic.

[0019] According to the invention, monomeric diisocyanates, which have aliphatic and / or cycloaliphatic isocyanate groups, are used.

[0020] Suitable monomeric diisocyanates can be produced by any method, e.g. by phosgenation or by a phosgene-free method, for example by urethane cleavage.

[0021] Suitable monomeric diisocyanates, hereinafter also referred to as starting diisocyanates, are, for example, those in the molecular weight range of 154 to 400 g / mol, such as 1,6-diisocyanatohexane (HDI), 1,5-diisocyanatopentane (PDI), 1,5-diisocyanato-2,2-dimethylpentane, 2,2,4- or 2,2,4-diisocyanate.2,4,4-Trimethyl-1,6-diisocyanatohexane, 1,8-Diisocyanatooctane, 1,9-Diisocyanatononane, 1,10-Diisocyanatodecane, 1,3- and 1,4-Diisocyanatocyclohexane, 1,4-Diisocyanato-3,3,5-trimethylcyclohexane, 1,3-Diisocyanato-2-methylcyclohexane, 1,3-Diisocyanato-4-methylcyclohexane, 1-Isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate; IPDI), 1-Isocyanato-1-methyl-4(3)-isocyanatomethylcyclohexane, 2,4'- and 4,4'-Diisocyanatodicyclohexylmethane (H12-MDI), 1,3- and 1,4-Bis(isocyanatomethyl)cyclohexane 4,4'-Diisocyanato-3,3'-dimethyldicyclohexylmethane, 4,4'-Diisocyanato-3,3',5,5'-tetramethyldicyclohexylmethane, 4,4'-Diisocyanato-1,1'-bi(cyclohexyl), 4,4'-Diisocyanato-3,3'-dimethyl-1,1'-bi(cyclohexyl), 4,4'-Diisocyanato-2,2',5,5'-tetramethyl-1,1'-bi(cyclohexyl), 1,8-Diisocyanato-p-menthane, 1,3-Diisocyanatoadamantane, 1,3-Dimethyl-5,7-diisocyanatoadamantane, and any mixtures of such diisocyanates.Further suitable diisocyanates can also be found, for example, in Justus Liebig's Annalen der Chemie, 562, 1949, 75-136.

[0022] Particularly preferred starting diisocyanates are aliphatic diisocyanates of the type mentioned, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, 2,4'- and 4,4'-diisocyanatodicyclohexylmethane, as well as any mixtures of these diisocyanates. 1,5-Diisocyanatopentane (PDI) and 1,6-Diisocyanatohexane (HDI) and mixtures thereof are especially suitable.

[0023] In the case that mixtures of different starting diisocyanates are used, it is particularly preferred that ≤ 30 wt.%, preferably ≤ 10 wt.% and particularly preferably ≥ 0 to ≤ 5 wt.% of the total starting diisocyanates used are cycloaliphatic diisocyanates and the remainder are aliphatic diisocyanates.

[0024] To produce the polyisocyanates (A) modified with allophane and optionally isocyanurate groups, a composition containing or consisting of component A1), A2) and optionally A1') is reacted.

[0025] In this process, the starting diisocyanates of component B) and hydroxy functional compounds of components A) and, if present, A'), are preferably reacted in an equivalent ratio of isocyanate groups to hydroxyl groups of 4 : 1 to 200 : 1, preferably of 5 : 1 to 50 : 1 and particularly preferably 7 : 1 to 30 : 1.

[0026] Allophanatization is a two-step process in which a hydroxyl group first reacts with an isocyanate group to form a urethane. This is then further reacted with another isocyanate group to form an allophanate. These two processes can be carried out simultaneously or sequentially. A sequential approach is preferred to better control the resulting exothermic reaction.

[0027] Urethanization is preferably carried out thermally and without a catalyst, but can also be catalyzed at lower temperatures. Suitable urethanization catalysts include those known to those skilled in the art, such as organotin compounds or amine catalysts. Examples of organotin compounds include dibutyltin diacetate, dibutyltin dilaurate, dibutyltin bisacetoacetonate, and tin carboxylates such as tin octoate. These tin catalysts can optionally be used in combination with amine catalysts such as aminosilanes or 1,4-diazabicyclo[2.2.2]octane. Further examples of urethanization catalysts suitable for use according to the invention are inorganic tin compounds such as SnCl₂ or tin-free compounds such as salts of bismuth, e.g., bismuth octoate, or other metals such as zinc compounds, titanium compounds, or zirconium compounds.The catalyst used in the subsequent allophanatization reaction can also be used in this step. This reaction would then take place at a lower temperature and / or with a lower catalyst concentration, so that little or no allophanatization occurs in this step.

[0028] It is also possible in this way to use the entire amount of allophanatization catalyst at elevated temperature and simplify the two-step process to a one-step reaction. However, this is not preferred, so the allophanatization catalyst is only added when the urethane groups are to be converted wholly or partially to allophanate groups.

[0029] The subsequent conversion to the allophanate can be carried out uncatalyzed as a thermally induced allophanatization. However, suitable catalysts are preferably used to accelerate the reaction. Catalysts can be employed that accelerate the formation of allophanate groups or of allophanate and simultaneously isocyanurate groups.

[0030] Suitable catalysts include, for example, simple tertiary amines such as triethylamine, tributylamine, N,N-dimethylaniline, N-ethylpiperidine, N,N'-dimethylpiperazine, or tertiary phosphines such as triethylphosphine, tributylphosphine or dimethylphenylphosphine.

[0031] Other suitable catalysts are the tertiary hydroxyalkylamines described in GB 2 221 465, such as triethanolamine, N-methyldiethanolamine, dimethylethanolamine, N-isopropyldiethanolamine and 1-(2-hydroxyethyl)pyrrolidine, or the catalyst systems known from GB 2 222 161, which consist of mixtures of tertiary bicyclic amines, such as DBU, with simple aliphatic alcohols with low molecular weight.

[0032] A variety of different metal compounds are also suitable as catalysts.

[0033] Suitable examples include the octoates and naphthenates of manganese, iron, cobalt, nickel, copper, zinc, zirconium, cerium, or lead, or their mixtures with acetates of lithium, sodium, potassium, calcium, or barium, as described in DE-A 3 240 613 as catalysts; the sodium and potassium salts of linear or branched alkanecarboxylic acids with up to 10 carbon atoms, such as those of propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid, caprylic acid, pelargonic acid, capric acid, and undecylenic acid, as known from DE-A 3 219 608; and the alkali or alkaline earth metal salts of aliphatic, cycloaliphatic, or aromatic mono- and polycarboxylic acids with 2 to 20 carbon atoms, such as sodium benzoate or potassium benzoate, as known from EP-A 0 100 129. the alkali metal phenoxides known from GB 1 391 066 A and GB 1 386 399 A, such as sodium phenoxide or potassium phenoxide;the alkali and alkaline earth metal oxides, hydroxides, carbonates, alkoxides and phenoxides known from GB 809 809, alkali metal salts of enolizable compounds, and metal salts of weak aliphatic and / or cycloaliphatic carboxylic acids, such as sodium methoxide, sodium acetate, potassium acetate, sodium acetoacetate, lead 2-ethylhexanoate and lead aphthenate; the basic alkali metal compounds complexed with crown ethers or polyether alcohols known from EP-A 0 056 158 and EP-A 0 056 159, such as complexed sodium or potassium carboxylates; the pyrrolidinone potassium salt known from EP-A 0 033 581; the monocyclic or polycyclic complex compounds of titanium, zirconium and / or hafnium known from EP-A 2 883 895, such as zirconium tetra-n-butoxide, zirconium tetra-2-ethylhexanoate and zirconium tetra-2-ethylhexylate;as well as tin compounds of the type described in the European Polymer Journal, 16, 1979, 147-148, such as dibutyltin dichloride, diphenyltin dichloride, triphenylstannanol, tributyltin acetate, tributyltin oxide, zinn octoate, dibutyl(dimethoxy)stannan and tributyltin imidazolate.;

[0034] Other suitable catalysts include, for example, the quaternary ammonium hydroxides known from DE-A 1 667 309, EP-A 0 013 880 and EP-A 0 047 452, such as tetraethylammonium hydroxide, trimethylbenzylammonium hydroxide, N-(2-hydroxyethyl)-N,N-dimethyl-N-(2,2'-dihydroxymethylbutyl)-ammonium hydroxide and 1-(2-hydroxyethyl)-1,4-diazabicyclo[2.2.2]octane hydroxide (monoadduct of ethylene oxide and water to 1,4-diazabicyclo[2.2.2]octane); the quaternary hydroxyalkylammonium hydroxides known from EP-A 37 65 or EP-A 10 589, such as N, N, N-trimethyl-N-(2-hydroxyethyl)-ammonium hydroxide, the trialkylhydroxyalkylammonium carboxylates known from DE-A 2631733, EP-A 0 671 426, EP-A 1 599 526 and US 4,789,705, such as N, N, N-trimethyl-N-2-hydroxypropyl-ammonium p-tert-butylbenzoate and N, N, N-trimethyl-N-2-hydroxypropylammonium 2-ethylhexanoate;the quaternary benzylammonium carboxylates known from EP-A 1 229 016, such as N-benzyl-N,N-dimethyl-N-ethylammonium pivalate, N-benzyl-N,N-dimethyl-N-ethylammonium-2-ethylhexanoate, N-benzyl-N,N,N-tributylammonium-2-ethylhexanoate, N,N-dimethyl-N-ethyl-N-(4-methoxybenzyl)-ammonium-2-ethylhexanoate or N,N,N-tributyl-N-(4-methoxybenzyl)-ammonium pivalate; the tetrasubstituted ammonium α-hydroxycarboxylates known from WO 2005 / 087828, such as tetramethylammonium lactate; the quaternary ammonium or phosphonium fluorides known from EP-A 0 339 396, EP-A 0 379 914 and EP-A 0 443 167, such as N-methyl-N,N,N-trialkylammonium fluorides with C 8 -C 10 alkyl groups, N,N,N,N,N-tetra-n-butylammonium fluoride, N,N,N-trimethyl-N-benzylammonium fluoride, tetramethylphosphonium fluoride, tetraethylphosphonium fluoride or tetra-n-butylphosphonium fluoride;the quaternary ammonium and phosphonium polyfluorides known from EP-A 0 798 299, EP-A 0 896 009 and EP-A 0 962 455, such as benzyltrimethylammonium hydrogen polyfluoride; the tetraalkylammonium alkyl carbonates known from EP-A 0 668 271, which are obtainable by reacting tertiary amines with dialkyl carbonates; or quaternary ammonium alkyl carbonates with a betaine structure; the quaternary ammonium hydrogen carbonates known from WO 1999 / 023128, such as choline bicarbonate; the quaternary ammonium salts obtained from tertiary amines and alkylating esters of phosphoric acids, such as reaction products of triethylamine, DABCO or N-methylmorpholine with dimethylmethanephosphonate, which are known from EP 0 102 482; or the tetrasubstituted ammonium salts of lactams known from WO 2013 / 167404, such as trioctylammonium caprolactamate or dodecyltrimethylammonium caprolactamate.;

[0035] These catalysts can be used individually or in any mixture with each other.

[0036] The catalysts are generally used in an amount of 0.0005 to 5.0 wt.%, preferably 0.0010 to 1.0 wt.% and particularly preferably 0.0015 to 0.1 wt.%, in each case based on the amount of starting diisocyanates A2) used.

[0037] The catalysts are added either as such or dissolved in a suitable organic solvent. Preferred catalyst solvents are those that have reactive groups towards isocyanates and can therefore be incorporated into the polymer. These include, for example, mono- or polyhydric alcohols such as methanol, ethanol, n -Propanol, Isopropanol, n -Butanol, n-Hexanol, 2-Ethyl-1-hexanol, ethylene glycol, propylene glycol, isomers of butanediol, 2-Ethyl-1,3-hexanediol, glycerol, ether alcohols such as 1-methoxy-2-propanol, 3-ethyl-3-hydroxymethyloxetane, tetrahydrofurfuryl alcohol, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol, dipropylene glycol, polyethylene glycols, polypropylene glycols, mixed polyethylene / polypropylene glycols and their monoalkyl ethers, ester alcohols such as ethylene glycol monoacetate, propylene glycol monolaurate, glycerin diacetate, glycerol monobutyrate or 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, unsaturated alcohols such as allyl alcohol, 1,1-Dimethylallyl alcohol or oleyl alcohol, araliphatic alcohols such as benzyl alcohol or monosubstituted amides such as N-methylformamide, N-methylacetamide, cyanoacetamide or 2-pyorrolidinone or mixtures of such solvents.

[0038] The dilution level of the catalyst solutions typically corresponds to a concentration of 0.05 to 20 wt.%, preferably 0.1 to 10 wt.%, particularly preferably 0.5 to 5 wt.%.

[0039] The quantities of alcohols used as catalyst solvents are not included in the quantities of components A1), A1') or B) used.

[0040] The reaction (U`) preferably takes place under an inert gas atmosphere at a temperature in the range of 0 °C to 150 °C, preferably in the range between 40 °C and 130 °C and particularly preferably between 70 °C and 120 °C.

[0041] The allophanatization is preferably continued until all urethane groups have been largely converted to allophanate groups. The degree of conversion is preferably at least 70% and particularly preferably at least 80%.

[0042] Once the desired degree of conversion is reached, the reaction can be stopped to prevent subsequent side reactions. This can be achieved, for example, by cooling the reaction mixture. Preferably, the reaction is stopped by adding a catalyst poison and optionally by subsequently heating the reaction mixture to a temperature above 80 °C.

[0043] Suitable catalyst poisons (stoppers) are known to those skilled in the art. These include, for example, hydrochloric acid, phosphoric acid, phosphonic acid, carboxylic acid chlorides such as acetyl chloride, benzoyl chloride or isophthaloyl dichloride, sulfonic acids or sulfonic acid esters such as methanesulfonic acid esters, p-toluenesulfonic acid, trifluoromethanesulfonic acid, perfluorobutanesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfonic acid methyl ester, p-toluenesulfonic acid ethyl ester, mono- or dialkyl phosphates such as tridecyl phosphate, dibutyl phosphate, dioctyl phosphate, or silylated acids such as trimethylsilyl methanesulfonic acid ester, trimethylsilyl trifluoromethanesulfonic acid ester, tris(trimethylsilyl) phosphate or diethyl(trimethylsily) phosphate.

[0044] The amount of catalyst poison required to stop the reaction depends significantly on the amount of catalyst used. Generally, an equivalent amount of the stopper is necessary, but since some of the catalyst can be deactivated by other means, a smaller amount of stopper may suffice.

[0045] The catalyst poison can also be added as such or in solution, with the catalyst solvents listed above being suitable, for example. In addition to these solvents, the starting isocyanates can also be used as solvents for the catalyst poisons.

[0046] After the reaction is complete, the starting diisocyanate is preferably separated from the reaction product. This is preferably done by distillation, for example at a pressure below 5 mbar, preferably below 1 mbar, and particularly preferably below 0.5 mbar, and for example at a temperature in the range of 100 to 200 °C, preferably in the range of 120 to 180 °C. The residual content of monomeric diisocyanate after distillation is preferably ≤ 0.50 wt.%, particularly preferably ≤ 0.3 wt.%, and particularly preferably < 0.10 wt.%.

[0047] Preferably, the polyisocyanates (A) modified with allophanate groups and optionally isocyanurate groups have a mean isocyanate functionality ≥ 4 and / or a weight-average molecular weight of ≥ 1000 g / mol, particularly preferably a mean isocyanate functionality ≥ 5 and / or a weight-average molecular weight of ≥ 1500 g / mol determined according to EN ISO 13885-1:2021-11.

[0048] The average isocyanate functionality of the modified polyisocyanate (A) is determined according to the following formula: F GPC = Mn GPC 100 × 42 % NCO Titr .

[0049] Where the isocyanate group content is given as wt.% and is determined titrimetrically according to DIN EN ISO 11909:2007-05 and the number-mean molecular weight is determined by GPC according to DIN EN ISO 13885-1:2021-11 using polystyrene as standard and tetrahydrofuran as eluent.

[0050] Preferably, the polyisocyanates (A) modified with allophanate groups and optionally isocyanurate groups have a viscosity of at most 50,000 mPas at 23 °C, preferably at most 25,000 mPas at 23 °C, particularly preferably at most 10,000 mPas at 23 °C, wherein the viscosity is determined according to DIN EN ISO 3219:1994-10 at a shear rate of 250 s-1.

[0051] The polyisocyanates (A) modified with allophane and optionally isocyanurate groups are, preferably after purification, hydrophilized by reaction with component B) (reaction U). Hydrophilization component B):

[0052] Component B) consists of non-ionic hydrophilic compounds with at least one isocyanate-reactive group.

[0053] These are, for example, monovalent polyalkylene oxide polyether alcohols with at least 30 wt% ethylene oxide units per molecule, having on average 5 to 70, preferably 6 to 40 and particularly preferably 7 to 20 alkylene oxide units, as can be obtained in a manner known per se by alkoxylation of suitable starter molecules (e.g. in Ullmann's Encyclopedia of Industrial Chemistry, 4th edition, Volume 19, Verlag Chemie, Weinheim, pp. 31-38).

[0054] Suitable starter molecules include, for example, saturated monoalcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, the isomers pentanols, hexanols, octanols and nonanols, n-decanol, n-dodecanol, n-tetradecanol, n-hexadecanol, n-octadecanol, cyclohexanol, the isomers methylcyclohexanols or hydroxymethylcyclohexane, 3-ethyl-3-hydroxymethyloxetane, or tetrahydrofurfuryl alcohol; diethylene glycol monoalkyl ethers such as diethylene glycol monobutyl ether; unsaturated alcohols such as allyl alcohol, 1,1-dimethylallyl alcohol or oleic alcohol, aromatic alcohols such as phenol, the isomers cresols or methoxyphenols, araliphatic alcohols such as benzyl alcohol, anise alcohol or cinnamyl alcohol;secondary monoamines such as dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, bis-(2-ethylhexyl)amine, N-methyl- and N-ethylcyclohexylamine or dicyclohexylamine, as well as heterocyclic secondary amines such as morpholine, pyrrolidine, piperidine or 1H-pyrazole.;

[0055] Preferred starter molecules are saturated monoalcohols and diethylene glycol monoalkyl ethers.

[0056] Suitable alkylene oxides for the alkoxylation reaction are in particular ethylene oxide and propylene oxide, which can be used in any order or in a mixture in the alkoxylation reaction.

[0057] Preferably, the polyalkylene oxide polyether alcohols are pure polyethylene oxide polyethers or mixed polyalkylene oxide polyethers, the alkylene oxide units of which consist of at least 30 mol%, preferably at least 40 mol%, of ethylene oxide units. Pure polyethylene oxide polyethers are particularly preferred.

[0058] The hydrophilized polyisocyanates (P) according to the invention are obtainable by reacting (U) the components A) and B) in an equivalent ratio of isocyanate groups of component A) to isocyanate-reactive groups of component B) of 1 : 0.5 to 1 : 0.02, preferably of 1 : 0.3 to 1 : 0.05.

[0059] The reaction can take place in the presence of catalysts C) and / or auxiliary and additive substances D). Catalysts C):

[0060] The urethanization catalysts already described above are suitable as catalysts that can accelerate the reaction of the isocyanate groups of component A) with the isocyanate-reactive groups of component B). Auxiliary and additive materials D):

[0061] The auxiliary and additive substances known in paint technology, such as UV absorbers, HALS stabilizers, pigments including metallic effect pigments, dyes, matting agents, fillers, leveling, wetting and deaerating additives, slip additives, nanoparticles, anti-yellowing additives, thickeners and additives to reduce surface tension, can be used.

[0062] Component D) also includes solvents. The same solvents can be used as previously described for the synthesis of polyisocyanate P'. The preferred ranges mentioned there apply analogously here. However, the use of solvents is not preferred.

[0063] The hydrophilized polyisocyanates (P) according to the invention are characterized by an allophane group content of at least 50 mol% (≥ 50 mol% to ≤ 100 mol%), based on the total amount of allophane and isocyanurate groups in the hydrophilized polyisocyanates (P). Preferably, they have an allophane group content of ≥ 50 mol% to ≤ 99 mol%, particularly preferably ≥ 60 mol% to ≤ 98 mol%, and most preferably ≥ 70 mol% to ≤ 98 mol%, in each case based on the total amount of allophane and isocyanurate groups in the hydrophilized polyisocyanates (P).

[0064] The isocyanurate group content is accordingly a maximum of 50 mol% (≥ 0 mol% to ≤ 50 mol%), preferably ≥ 1 mol% to ≤ 50 mol%, particularly preferably ≥ 2 mol% to ≤ 40 mol%, most preferably ≥ 2 mol% to ≤ 30 mol%, based on the total amount of allophanate groups and isocyanurate groups in the hydrophilized polyisocyanates (P).

[0065] The levels of allophanate groups and isocyanurate groups in the hydrophilized polyisocyanates (P) are determined by NMR spectroscopic analysis.

[0066] In addition to modification with allophanate groups and, if applicable, isocyanurate groups, as well as the urethane groups from hydrophilization, the hydrophilized polyisocyanates (P) may also contain minor amounts of urea, uretdione, and / or iminooxadiazindeione groups. Urethane groups may also be retained, for example, from incomplete allophanatization. Similarly, uretdione and iminooxadiazindeione groups may occur as a side reaction of trimerization.

[0067] "In subordinate amounts" means that the total proportion of urea, uretdione, and / or iminooxadiazindeione groups is a maximum of 15 mol% (≥ 0 to ≤ 15 mol%), preferably a maximum of 10 mol% (≥ 0 to ≤ 10 mol%), based on the total amount of allophane and isocyanurate groups in the hydrophilized polyisocyanate (P). Their contents are also determined by NMR spectroscopic analysis.

[0068] The mol% concentrations of allophanate and isocyanurate groups, as well as urethane, urea, uretdione, and / or iminooxadiazindeione groups, are preferably calculated from the integrals of proton-decoupled <13C NMR spectra. A Bruker AV III HD 600 NMR spectrometer with probe Z150361_001 (CP BBO 600SS3 BB-H&F-05 ZE T) was used for this purpose, with 512 scans. Based on experience, with a repetition time (D1) of 4 s and a measurement time (AQ) of 1.57 s, it is assumed that very similar carbonyl carbon atoms are comparable via integration. In the case of hexamethylene diisocyanate-based polyisocyanates dissolved in CDCls, the individual structural elements exhibit the following chemical shifts (in ppm): Allophanate: 155.7 and 153.8 (one carbon atom each); Isocyanurate: 148.4 (three carbon atoms); Iminooxadiazindione: 147.8, 144.3 and 135.3 (one carbon atom each); Uretdione: 157.1 (two carbon atoms); Urethane: 156.3 (one carbon atom); Urea: 158-161 (one carbon atom).

[0069] The hydrophilized polyisocyanates (P) according to the invention preferably have a number-average isocyanate functionality of ≥ 4 and / or a weight-average molecular weight of ≥ 1,350 g / mol, determined according to DIN EN Iso 13885-1:2021-11.

[0070] The number-average isocyanate functionality is determined analogously to the above explanations for determining the number-average isocyanate functionality of (A).

[0071] Preferably, the hydrophilized polyisocyanates (P) have a viscosity of at most 25,000 mPas at 23 °C, preferably at most 10,000 mPas at 23 °C, particularly preferably at most 8,000 mPas at 23 °C, wherein the viscosity is determined according to DIN EN ISO 3219:1994-10 at a shear rate of 250 s-1.

[0072] The present invention also relates to the use of the hydrophilized polyisocyanates (P) according to the invention for the production of coatings, sealants and adhesives, as well as the coatings, sealants and adhesives themselves obtained in this way. These can be one- or two-component systems.

[0073] To produce one-component systems, the isocyanate groups of the hydrophilized polyisocyanates (P) according to the invention can be blocked. In one embodiment, the isocyanate groups of the hydrophilized polyisocyanates (P) according to the invention are therefore present at least partially in a form blocked by at least one blocking agent F). This means that at least 70 mol%, preferably at least 85 mol%, and particularly preferably at least 95 mol% of the isocyanate groups are present in a form blocked by blocking agents.

[0074] A blocking agent is a compound that reacts with an isocyanate group and can be cleaved from it again under defined conditions. All blocking agents commonly used in polyurethane chemistry can be employed for this purpose. Examples include alcohols, lactams, oximes, malonic esters, alkylacetoacetates, triazoles, imidazoles, pyrazoles and amines such as butanone oxime, diisopropylamine, 1,2,4-triazole, dimethyl-1,2,4-triazole, imidazole, diethyl malonate, acetoacetic acid esters, acetone oxime, 3,5-dimethylpyrazole, ε-caprolactam, N-methyl, N-ethyl, N-(iso)propyl, Nn-butyl, N-isobutyl, N-tert-butylbenzylamine or 1,1-dimethylbenzylamine, N-alkyl-N-1,1-dimethylmethylphenylamine, adducts of benzylamine to compounds with activated double bonds such as malonic esters, N,N-dimethylaminopropylbenzylamine and other tertiary amino groups containing optionally substituted benzylamines and / or dibenzylamine.Other examples of suitable blocking agents are CH-acidic cyclic ketones with an electron-withdrawing group in the ortho position to the keto group, such as an ester group, a sulfoxide group, a sulfone group, a nitro group, a phosphonate group, a nitrile group, an isonitrile group or a carbonyl group, as well as hydrocarbon resins with phenolic OH groups and optionally substituted phenols, such as cashew nut shell products containing at least cardanol and / or cardol, as described, for example, in WO 2021 / 204741 A1.

[0075] In a preferred embodiment, the hydrophilized and optionally at least partially blocked polyisocyanates (P) according to the invention are used in the form of an aqueous dispersion in the production of the coating materials, sealants and adhesives.

[0076] The coatings, sealants, and adhesives may contain compounds with isocyanate-reactive groups. The isocyanate-reactive compounds preferably have a functional group of ≥ 2 to ≤ 6 and are preferably selected from the group consisting of -OH, -SH, -NH, -NH₂, and -(H)NN₂H.

[0077] Preferred are hydroxy functional compounds, for example the hydroxy functional compounds already described above.

[0078] In a preferred embodiment, polyacrylate polyols, polyester polyols and / or polyester urethane polyols are used.

[0079] The hydroxy functional compounds can preferably also be used in the form of aqueous dispersions, such as polyacrylate dispersions, polyacrylate emulsions, alkyd dispersions, polyurethane-polyacrylate dispersions, polyurethane dispersions or aqueous epoxy resins.

[0080] Examples of such dispersions are the products of the type Bayhydrol A (polyacrylate polyols), Bayhydrol E (polyester polyols) and Bayhydrol U (polyester urethane polyols) marketed by Covestro Deutschland AG.

[0081] Furthermore, non-reactive polyurethane dispersions can also be used. In this context, this refers to a polyurethane or polyurethane urea, preferably dispersed in water, and comprising only unreactive groups towards isocyanate groups. Preferably, these unreactive groups are urethane and / or urea and / or carboxylate and / or sulfonate groups. Due to the manufacturing process, it is possible that such dispersions contain small amounts of amine end groups.

[0082] Examples of non-reactive polyurethane dispersions are the products of the type Impranil, Baybond, Bayhydrol UH marketed by Covestro Deutschland AG, such as Impranil DLS, Impranil DLN, Impranil DLC / F, Baybond PU 406, Baybond PU 330, Bayhydrol UH 25 340 / 1 etc.

[0083] It is also conceivable to use other crosslinking dispersions, such as polyisocyanates, which may optionally also have hydrophilizing groups incorporated and contain free or possibly blocked isocyanate groups, or polyaziridines.

[0084] The coating materials, sealants and adhesives according to the invention may also contain catalysts for controlling the curing rate, for example the catalysts commonly used in isocyanate chemistry, such as tert-amines like triethylamine, pyridine, methylpyridine, benzyldimethylamine, N,N-endoethylenepiperazine, N-methylpiperidine, pentamethyldiethylenetriamine, N,N-dimethylaminocyclohexane, N,N'-dimethylpiperazine or metal salts like iron(III) chloride, zinc chloride, zinc 2-ethylcaproate, tin(II) octanoate, tin(II) ethylcaproate, dibutyltin(IV) dilaurate, bismuth(III) 2-ethylhexanoate, bismuth(III) octoate or molybdenum glycolate.

[0085] The coating materials, sealants and adhesives according to the invention may also contain the following components: additives for the formulation of coating materials such as leveling agents, wetting agents, adhesion promoters, thickeners, antioxidants, color pigments, pigments, coalescing agents, defoamers, deaerators, etc.

[0086] Another object of the invention is substrates comprising coating materials, sealants or adhesives in uncured, partially cured or fully cured form.

[0087] Depending on the application, substrates such as glass, metal, fabric, leather, fibers, paper, wood, plastic, stone and concrete are suitable.

[0088] Another object of the invention is a method for coating a substrate comprising the steps i) Providing a substrate that may be pre-treated, ii) Applying a coating material available according to the above use, and iii) partially or completely hardening the coating material. Examples:

[0089] Unless otherwise stated, all percentages refer to weight.

[0090] The NCO content was determined titrimetrically according to DIN EN ISO 11909:2007-05.

[0091] The residual monomer contents were measured by gas chromatography with an internal standard according to DIN EN ISO 10283:2007-11.

[0092] All viscosity measurements were performed using a Physica MCR 51 rheometer from Anton Paar Germany GmbH (DE) according to DIN EN ISO 3219:1994-10 at a shear rate of 250 s-1.

[0093] The gloss of the coatings obtained was measured reflectometrically according to DIN EN ISO 2813:1999-06 at a 20° angle.

[0094] The determination of the pendulum damping according to König was carried out according to DIN EN ISO 1522:2007-04 on glass plates.

[0095] 13C-NMR spectra were acquired using a Bruker AV III HD 600 NMR spectrometer with probe Z150361_001 (CP BBO 600SS3 BB-H&F-05 ZE T). 512 scans were performed, with a repetition time (D1) of 4 s and a measurement time (AQ) of 1.57 s.

[0096] Molecular weights were measured by gel permeation chromatography according to DIN EN ISO 13885-1:2021-11. Four columns were used (2x PSS SDV 50A, 5µ, 2x PSS SDV 100A, 5µ).

[0097] To determine the dispersibility, 4 g of water were rapidly mixed with 1 g of resin on a shaking table. The particle size was then determined using laser correlation spectroscopy.

[0098] To test the coatings for solvent resistance, small amounts of the solvents xylene, 1-methoxypropyl-2-acetate, ethyl acetate, and acetone were placed in test tubes and a cotton ball was placed at the opening to create a solvent-saturated atmosphere inside the test tubes. The test tubes, with the cotton ball still attached, were then placed on the surface of the coatings applied to glass and left there for 1 or 5 minutes. After wiping off the solvent, the film was inspected for damage / softening / loss of adhesion and rated (0 = no change, 5 = film completely dissolved). The ratings for the four solvents are given in the following order: xylene, 1-methoxypropyl-2-acetate, ethyl acetate, and acetone, as four consecutive numbers.

[0099] Water resistance was assessed according to the criteria for solvent resistance described above. For this purpose, a drop of water was placed on the surface of the coatings applied to glass. The drop was covered with a snap-top glass jar and left to stand for 24 hours before being wiped off to assess the damage pattern.

[0100] The Hammer Polish Test is a test in which a 1kg hammer is used to rub some steel wool across a surface. One cycle consists of moving the hammer back and forth.

[0101] Bayhydur®< 304 is a commercially available product of Covestro Deutschland AG. It is a hydrophilic isocyanurate-based and allophane-modified polyisocyanate. Allophanet 1

[0102] In a 100 L reactor, 49.56 kg of hexamethylenediisocyanate (Desmodur®< H, Covestro Deutschland AG) was placed, inerted three times with nitrogen, and heated to 100 °C. A mixture of 554.6 g of trimethylolpropane and 690.3 g of 1,3-butanediol was added slowly, dropwise, over one hour. The mixture dissolved immediately in the polyisocyanate. Stirring continued at 100 °C for approximately 1.5 hours until an NCO of 46.5% was reached. Subsequently, the catalyst (2.54 g of zinc octoate dissolved in 48.26 g of 2-ethylhexanol) was added in four equal portions, successively (approximately five minutes each). Stirring continued at 100 °C for approximately one hour until an NCO of 44.2% was reached. The reaction was then stopped by adding the stopper solution (5.08 g ortho-phosphoric acid in 45.72 g 2-ethylhexanediol).

[0103] After filtration, the excess HDI was separated using a thin-film evaporator at 130 °C. 0.22 g of isophthaloyl chloride in 4.14 g of isopropanol was added to the resin (approx. 11 kg) for stabilization. It had the following properties: NCO content: 19,8 % Monomeric HDI: 0,07 % Viscosity (23°C): 5200 mPas Allophanet 2

[0104] One hundred parts of hexamethylene diisocyanate (HDI) were placed in the solution and heated to 105 °C. At this temperature, ten parts of trimethylolpropane were added while stirring. This caused a cloudiness that cleared up after some time. After completion of the urethanation reaction, the reaction temperature was lowered to 95 °C. Subsequently, the trimerization and allophantation reactions were initiated by adding a 0.5% trimethylbenzylammonium hydroxide solution in 2-ethylhexanol. Upon reaching an NCO value of 36%, the reaction was stopped by adding a stopper solution (10% dibutyl phosphate in HDI) in a weight ratio of 100 parts catalyst solution to 3 parts stopper solution. The mixture was stirred for another 30 minutes at 95 °C, and then the remaining monomeric HDI was separated in a short-path evaporator at 140 °C and 0.1 mbar. The resulting polyisocyanate exhibited the following properties. NCO content: 19,3 % Monomeric HDI: 0,09 % Viscosity (23°C): 35000 mPas Hydrophilized polyisocyanate 1 (according to the invention)

[0105] 400 g of allophanate 1 were placed in a 1 L four-necked round-bottom flask equipped with a reflux condenser, heated oil bath, mechanical stirrer, internal thermometer, and dropping funnel. The flask was inerted with nitrogen and heated to 50 °C. First, 90 mg of dibutyltin dilaurate were added, followed by 57.14 g of MPEG 350 slowly added dropwise until the target NCO content of 15.92% was reached. Finally, 50 mg of dibutyl phosphate were added, and the reaction mixture was homogenized. A colorless resin was obtained. NCO content: 15,7 % Viscosity (23°C): 7670 mPas Particle size after dispersion 159 nm, stable Hydrophilized polyisocyanate 2 (not according to the invention)

[0106] In a 250 ml four-necked round-bottom flask equipped with a reflux condenser, heated oil bath, mechanical stirrer, internal thermometer, and dropping funnel, 102 g of allophanate 2 were placed, inerted with nitrogen, and heated to 50 °C. First, 20 mg of dibutyltin dilaurate were added, followed by 18 g of MPEG 350 slowly added dropwise until the target NCO content of 14.65% was reached. Finally, 10 mg of dibutyl phosphate were added, and the reaction mixture was homogenized. A colorless resin was obtained. NCO content: 14,61 % Viscosity (23°C): 19,750 mPas Particle size after dispersion 339nm, decays quickly Application example

[0107] Varying weight parts of a commercially available polyacrylate dispersion (Bayhydrol® < A 2058; Covestro Deutschland AG, Leverkusen, Germany) with a solids content of 42% by weight were mixed with 0.4 parts by weight of a commercially available wetting agent (Byk 347, Byk-Chemie GmbH), 0.3 parts by weight of a commercially available wetting agent (Byk 333, Byk-Chemie GmbH), and varying proportions of water, and thoroughly mixed by intensive stirring. The formulation was allowed to stand for one day.

[0108] Subsequently, varying weights of the hydrophilized polyisocyanates 1 and Bayhydur®< 304 were mixed with different proportions of methoxypropyl acetate and 3 parts water each. This mixture was blended for two minutes at 2000 min⁻¹ using a dissolver. The mixtures were then applied to a glass plate using a 120 µm wet squeegee and dried for 30 minutes at 80 °C, followed by 16 hours of aging at 60 °C.

[0109] Table 1 below shows the compositions of the coating compositions in parts by weight, and Table 2 shows the results of the application-related tests of the coatings obtained in comparison. Table 1 : Inventive example 1 and comparative example 2 - Composition of the coating materials Example 1 (according to the invention) 2 (Comparison) Bayhydrol A 2058 44,2 47,8 BYK ®< -347 0,4 0,4 BYK ®< -333 0,3 0,3 Water 6,3 5,4 Hydrophilized polyisocyanate 1 21,0 -- Bayhydur ®< 304 -- 19,5 Methoxypropyl acetate 7,8 6,6 Water 3,0 3,0 Solids (wt.%) 48 48 NCO / OH ratio 1,5 1,5 solvents 9,7% 8,3% Table 2: Inventive example 1 and comparative example 2 - Coating properties Example 1 (according to the invention) 2 (Comparison) Layer thickness [µm] after drying 46 37 Pendulum damping (König) 69 109 Water resistance 24 h 0 1 Solvent resistance 5 min (X, MPA, EA, A) 5 min 0 / 0 / 1 / 3 1 / 1 / 2 / 3 Scratch resistance hammer polish test start 80 85 Gloss 20° after 10 cycles 64 46 relative gloss retention 80% 54%

[0110] The hydrophilized polyisocyanate 1 according to the invention has a significantly lower viscosity compared to the hydrophilized polyisocyanate 2 according to the non-inventional invention and, after dispersion, yields a dispersion that is stable for many hours. In contrast, the hydrophilized polyisocyanate 2 according to the non-inventional invention yields a very coarse dispersion that disintegrates after a short time and therefore could not be investigated for practical applications.

[0111] As can be seen from Table 2, the hydrophilized isocyanate system according to the invention (Example 1) achieves better solvent resistance than the non-inventive system (Comparative Example 2). Water resistance is also increased. Furthermore, the scratch test shows better gloss retention and thus better scratch resistance.

Claims

1. Hydrophilized polyisocyanates (P) obtainable from the reaction (U) A) of a polyisocyanate modified with allophane and optionally isocyanurate groups, which has a proportion of allophane groups ≥ 50 mol%, preferably ≥ 50 mol% to ≤ 99 mol%, preferably ≥ 60 mol% to ≤ 98 mol%, particularly preferably ≥ 70 mol% to ≤ 98 mol%, in each case based on the total amount of allophane and isocyanurate groups in the modified polyisocyanate and determined by NMR spectroscopic analysis, and which is obtainable from the reaction (U`) A1) of a mixture of A11) at least one monomeric triol and A12) at least one monomeric diol, with A2) at least one monomeric diisocyanate having aliphatic and / or cycloaliphatic isocyanate groups, with B) at least a non-ionically hydrophilizing compound with at least one isocyanate-reactive group, optionally in the presence of C) at least one,the reaction of the isocyanate groups of component A) with the isocyanate-reactive groups of component B) accelerating catalyst and / or D) at least one auxiliary or additive.

2. Hydrophilized polyisocyanates (P) according to claim 1, wherein the at least one monomeric triol of component A11) has up to 15 carbon atoms and / or the at least one monomeric diol of component A12) has up to 15 carbon atoms.

3. Hydrophilized polyisocyanates (P) according to claim 1 or 2, wherein the at least one monomeric triol of component A11) is 1,1,1-trimethylolpropane, and / or the at least one monomeric diol of component A12) is selected from the group consisting of 1,3-butanediol and 1,4-butanediol.

4. Hydrophilized polyisocyanates (P) according to any one of claims 1 to 3, wherein the polyisocyanates (A) modified with allophane and optionally isocyanurate groups have a number-average isocyanate functionality of ≥ 4, based on the solids content of (A), and / or a weight-average molecular weight of ≥ 1,000 g / mol, determined according to DIN EN Iso 13885-1:2021-11.

5. Hydrophilized polyisocyanates (P) according to any one of claims 1 to 4, wherein component B) is a monovalent polyalkylene oxide polyether alcohol having on average 5 to 70, preferably 5 to 55 ethylene oxide units per molecule and an ethylene oxide unit content of ≥ 30 wt.%.

6. Hydrophilized polyisocyanates (P) according to claim 5, wherein pure polyethylene oxide polyether alcohols are used.

7. Hydrophilized polyisocyanates (P) according to any one of claims 1 to 6 with a number-average isocyanate functionality of ≥ 4 and / or a weight-average molecular weight of ≥ 1,350 g / mol determined according to DIN EN ISO 13885-1:2021-11.

8. Hydrophilized polyisocyanates (P) according to any one of claims 1 to 7 having a viscosity of at most 25,000 mPas at 23°C, preferably at most 10,000 mPas at 23°C, particularly preferably at most 8,000 mPas at 23°C, wherein the viscosity is determined according to DIN EN ISO 3219:1994-10 at a shear rate of 250 s-1 .

9. Use of hydrophilized polyisocyanates (P) according to any one of claims 1 to 8 for the manufacture of coatings, sealants or adhesives.

10. Use according to claim 9, wherein the hydrophilized polyisocyanates (P) are in the form of an aqueous dispersion.

11. Coating materials, sealants or adhesives obtainable from the use according to claim 10 or 9.

12. Use according to claim 10 or 9 or coating materials, sealants or adhesives according to claim 11, wherein the systems are 1- or 2-component.

13. Substrates comprising coating materials, sealants or adhesives according to claim 11 or 12 in uncured, partially cured or fully cured form.

14. A method for coating a substrate comprising the steps of i) providing a substrate that may be pretreated, ii) applying a coating material according to claim 11 or 12, and iii) partially or completely hardening the coating material.

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